Leads implanted in or about the heart have been used to reverse certain life threatening arrhythmia, or to stimulate contraction of the heart. Electrical energy is applied to the heart via electrodes on the leads to return the heart to normal rhythm.
Materials chosen for lead conductors can have varying properties, with some being more corrosion resistant, some being stronger, some having better electrical properties, and so on. Design of new types of leads is facilitated by conductors having better overall properties.